This rim is built specifically for the rigorous demand a unicycle puts on a rim. Its the same rim as the double walled eyelet alloy rim.
Should you want to build the wheel, here is a link to the Spoke Calculator so you can find the correct spoke length you need.
Width Outside: 42mm
Width Inside: 32mm
Spoke Holes: 36
Material: High Quality 6061 heat treated aluminum with box section
Finish: Grey powdercoat
Nipple Eyelets: Stainless Steel